Road rage is aggressive or angry behavior by a driver of an automobile or other road vehicle. Such behavior might include rude gestures, verbal insults, deliberately driving in an unsafe or threatening manner, or making threats. Road rage can lead to altercations, assaults, and collisions that result in injuries and even deaths. It can be thought of as an extreme case of aggressive driving.
The term originated in the United States in 1987–1988 (specifically, from Newscasters at KTLA, a television station in Los Angeles), when a rash of freeway shootings occurred on the 405, 110, and 10 freeways in Los Angeles, California. These shooting sprees even spawned a response from the AAA Motor Club to its members on how to respond to drivers with road rage or aggressive manoeuvers and gestures.
The following are common manifestations of road rage:
- Generally aggressive driving, including sudden acceleration, braking, and close tailgating
- Cutting others off in a lane, or deliberately preventing someone from merging
- Chasing other motorists
- Flashing lights and/or sounding the horn excessively
- Yelling or exhibiting disruptive behavior at roadside establishments
- Driving at high speeds in the median of a highway to terrify drivers in both lanes
- Rude gestures (such as "the finger")
- Shouting verbal abuses or threats
- Intentionally causing a collision between vehicles
- Hitting other vehicles
- Assaulting other motorists, their passengers, cyclists, or pedestrians
- Exiting the car to attempt to start confrontations, including striking other vehicles with an object
- Threatening to use or using a firearm or other deadly weapon
- Throwing projectiles from a moving vehicle with the intent of damaging other vehicles
In the U.S., more than 300 cases of road rage annually have ended with serious injuries or even fatalities – 1200 incidents per year, according to the AAA Foundation study, and rising yearly throughout the six years of the study that examined police records nationally. A number of studies have found that individuals with road rage were predominantly young (33.0 years of age on average) and male (96.6%). In Germany, a gun-weilding truck driver was accused of firing at over 762 vehicles and arrested in 2013, an exceptional case of road rage. According to authorities, the autobahn sniper was motivated by "annoyance and frustration with traffic." 
In some jurisdictions, there may be a legal difference between "road rage" and "aggressive driving". In the U.S., only a few states have enacted special aggressive driving laws, where road rage cases are normally prosecuted as assault and battery (with or without a vehicle), or "vehicular homicide" (if someone is killed).
The legal definition of road rage encompasses a group of behaviors expressed while driving or stemming from traffic-related incidents. The National Highway Traffic Safety Administration defines road rage as when “an individual commits a combination of moving traffic offenses so as to endanger other persons or property; an assault with a motor vehicle or other dangerous weapon by the operator or passenger(s) of one motor vehicle on the operator or passenger(s) of another motor vehicle caused by an incident that occurred on a roadway” (National Highway Traffic Safety Administration). This definition makes an important distinction between a traffic offense and a criminal offense. However, many in the field of psychoanalysis say this definition is lacking. Psychologists are now considering a new label for road rage. Many claim that road rage is really a form of mental illness or a combination of emotional responses culminating in a pattern of behavior or syndrome. This implies that the behavior may be outside the control of the perpetrator. This concept is legally precarious as it could excuse many drivers of their dangerous behavior and aggressive driving. Less-than-honest motor vehicle operators and their legal defense teams may use this new view (of road rage as a syndrome) as a catch-all defense against charges of road way altercations.
Road rage as a medical condition
As early as 1997, therapists in the United States were working to certify road rage as a medical condition. It is not an official mental disorder in the Diagnostic and Statistical Manual of Mental Disorders. According to an article published by the Associated Press in June 2006, the behaviors typically associated with road rage can be the result of intermittent explosive disorder. This conclusion was drawn from surveys of some 9,200 adults in the United States between 2001 and 2003 and was funded by the National Institute of Mental Health. The cause of intermittent explosive disorder has not been described to date. There are differing views on whether or not "road rage" is a mental issue. Regardless of whether it is or not, there are alternative solutions for overcoming this handicap.
Road rage is a relatively serious act: It may be seen as an endangerment of public safety. It is, however, not always possible to judge intent by external observation, so "road ragers" who are stopped by police may be charged with other offences such as careless or reckless driving, and may resolve in fines. 
In some jurisdictions, such as the American Commonwealth of Virginia, it is easier to prosecute road rage as reckless driving instead of aggressive driving simply because the burden of proof does not require "intent" to successfully convict.
It is likely that those causing serious injury or death during "road rage" incidents will suffer more serious penalties than those applicable to similar outcomes from simple negligence. In April 2007, a Colorado driver was convicted of first-degree murder for causing the deaths of two motorists in November 2005. He will serve a mandatory sentence of two consecutive life terms.
Fourteen U.S. states have passed laws against aggressive driving. Only one state, California, has turned "road rage" into a legal term of art by giving it a particular meaning. In Virginia, aggressive driving is punished as a lesser crime (Class 2 misdemeanour) than reckless driving (Class 1 misdemeanour).
In New Zealand road rage is, in itself, not an offence. However, when another road-user is physically assaulted or killed, then the offending parties are prosecuted for the specific offence committed. Drivers have a legal duty to take reasonable care to avoid endangerment of human life when operating a vehicle (s 156 Crimes Act 1961); failure to discharge this duty, such as an act of aggressive driving, can give rise to liability in criminal nuisance (s 146 Crimes Act 1961). Ramming a vehicle constitutes intentional or reckless damage to property, a criminal offence, with a maximum penalty of 7 years imprisonment (s 269 Crimes Act 1961). The New Zealand Police generally regard "road rage" complaints as a low priority and the courts currently have no powers to disqualify drivers who physically assault another road user.
In New South Wales, Australia, road rage is considered an extremely serious act. Any person who chases another motorist or shows intimidating and/or bullying towards another road user can be charged with predatory driving, a serious offence that can leave the culprit in jail for up to 5 years. Offenders can also be fined A$100,000 and disqualified from driving, regardless of whether or not he or she intended to harm the victim physically. If the predatory driving results in a physical assault or harm, and/or the victim's car was intentionally damaged, penalties can be much more severe.
Additionally, most common-law countries prohibit common assault, which could apply to road rage where the personal safety of the victim is seen to be threatened. The common law regards assault as both a criminal and civil matter, leading to both public criminal penalties and private civil liabilities.
In the UK, road rage can result in criminal penalties for assault or more serious offences against the person. The Public Order Act 1986 can also apply to road rage. Sections 4A and 5 of the 1986 Act prohibit public acts likely to cause harassment, alarm or distress. Section 4 also prohibits threatening, abusive or insulting words or behaviour with intent to cause a victim to believe that violence will be used against himself or another.
Road rage, insults and rude gestures in traffic can lead to fines and even prison sentences to drivers who shout insults or make offensive gestures while driving. 
A 2007 study of the largest U.S. metropolitan areas concluded that the cities with the least courteous drivers (most road rage) are Miami, Phoenix, New York, Los Angeles, and Boston. The cities with the most courteous drivers (least road rage) are Minneapolis, Nashville, St. Louis, Seattle, and Atlanta.
In spite of this, in 2009, New York, Dallas/Fort Worth, Detroit, Atlanta and Minneapolis/St. Paul were rated the top five "Road Rage Capitals" of the United States.
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- Extensive data regarding road rage and driving behavior can be found at the US National Highway Traffic Safety Administration (NHTSA) website.
- Mobility without Mayhem: Safety, Cars, and Citizenship, by Jeremy Packer. This book contains a chapter about road rage.
- PlateWire A web site where motorist posts license plates along with road rage details US